From: Paul Brannan <pbrannan@...>
Date: 2003-11-06T23:22:06+09:00
Subject: Re: The new allocation scheme and extensions

On Sun, Nov 02, 2003 at 06:43:14AM +0900, Shu-yu Guo wrote:
> In 1.6, when writing an extension which required Data_Wrap_Struct, the
> programmer would define the singleton method "new" to handle that. In 1.8, the
> scheme seems to be to write an allocate function (to pass to
> rb_define_alloc_func) then do the rest of the code in the intialize function.
> Indeed, that's what Class#new does now.
> 
> So my question is, when writing extensions, is the "old" way of defining the
> singleton method "new" deprecated? Are we to use the new allocate/initialize
> way now?

You can do this on 1.6:

  inline VALUE ruby_16_new(int argc, VALUE * argv, VALUE klass)
  {
    VALUE obj = rb_funcall(klass, rb_intern("allocate"), 0);
    rb_obj_call_init(obj, argc, argv);
    return obj;
  }

  rb_define_singleton_method(klass, "allocate", allocate_func, -1);
  rb_define_singleton_method(klass, "new", ruby_16_new, -1);
  rb_define_method(klass.v, "initialize", initialize_func, -1);

This allows you to divide your code into allocate/initialize similar to
how you would on 1.8.

Paul